This is painful, but it has to be noted.

In a phone call, [Sen. Sanders's policy director Warren] Gunnels explained the $1.1 trillion gap. It comes down to five factors:

...Sanders assumes $324 billion more per year in prescription drug savings than Thorpe does. Thorpe argues that this is wildly implausible. "In 2014 private health plans paid a TOTAL of $132 billion on prescription drugs and nationally we spent $305 billion," he writes in an email. "With their savings drug spending nationally would be negative." (Emphasis mine.) The Sanders camp revised the number down to $241 billion when I pointed this out.

...When I pointed out that the yearly savings numbers they were presenting on prescription drugs were literally impossible, the Sanders camp revised the number to $241 billion — huge and arguably implausible but not larger than total annual spending on prescription drugs.

“We are not allowed to negotiate drug prices. Can you believe it? We pay about $300 billion more than we are supposed to, than if we negotiated the price. So there’s $300 billion on day one we solve.” –Donald Trump, remarks at Plymouth State University, Holderness, N.H., Feb. 7, 2016

“So I said to myself wow, let me do some numbers. If we competitively bid drugs in the United States, we can save as much as $300 billion a year.” –Trump, remarks in Manchester, N.H., Feb. 8

...total spending in Medicare Part D (prescription drugs) in 2014 was $78 billion. So Trump, in effect, is claiming to save $300 billion a year on a $78 billion program. That’s like turning water into wine.

It’s possible that Trump is being sloppy and when he discusses Medicare, he really means to say he would force government-led pricing on all prescription drugs. But the numbers don’t add up that way either.

In fact, depending on the source you consult, total annual spending on prescription drugs in the United States is between $298 billion a year to $423 billion. So that would mean Trump is claiming that he can eliminate virtually any cost to prescription drugs. It would suddenly be free!

Prescription Drugs: Retail prescription drug spending accelerated in 2014, growing 12.2 percent to $297.7 billion compared to the 2.4 growth in 2013. The rapid growth in 2014 was due to increased spending for new medications (particularly for specialty drugs such as hepatitis C), a smaller impact from patent expirations, and brand-name drug price increases. Private health insurance, Medicare, and Medicaid spending on prescription drugs all accelerated in 2014.